In this year's MacTaggart lecture at the Edinburgh Television Festival, Jeremy Paxman repeatedly asked the question, "What is television for?" He did so in an entertaining way and provided commentators with some memorable one-liners. But did he answer the question he posed? In today's MediaGuardian we've asked some senior figures from the industry - including Paxman himself - to do just that.

Jeremy PaxmanNewsnight anchor

The function of television seems to me perfectly simple. It's to open our eyes. Lord Reith was a dour old codger, but that original distillation about informing, educating and entertaining will do as well today as ever it did.

When I'm feeling gloomy, it seems to me that the original mission has been lost sight of, in a mad scramble to make money and sell garbage. Too many of the medium's ruling class seem to answer the question "what is television for?" (if they ever bother to think about it at all) by saying "to make money".

I understand perfectly well that companies cannot make programmes if they don't make money. The failure is on the part of the managements, commissioners and regulators. The problem is that no one in a senior position has any idea what the future holds. The digital future offers the enchanting prospect of irrelevance for everyone.

How to fill the void? Well, obviously, live hangings and sex would build audience share. In the absence of those, we can just make a lot of noise. Too much television, from news to entertainment, seems to have that as its only objective. The problem with that approach is that, sooner or later, someone else comes along who can make a bigger bang. The game's not up yet. In fact, there's no certainty that it ever will be. But for that to be the case we need to rediscover a clear sense of purpose.

Armando IannucciProgramme-maker, presenter, writer

To the old perennials (to entertain, to educate and to inform), maybe we should now add a fourth: to surprise. It's easy to surrender to the oncoming technical revolution, where any programme ever made will become available on any media platform at any time the viewer wants, and just assume that creative idiosyncrasy will be swept away in this digital tsunami. Far from it: the lesson from the internet is that people gravitate towards sites that will point them in the direction of good things. How often do you click on something unexpected that looks more interesting than the thing you were looking for in the first place?

We're all constantly on the look-out for surprises, as long as we know they'll be good. British TV has a real chance to mark itself out as a place where good, surprising TV originates. This will only happen if we're more upfront and confident about what we're making. For example, BBC3 and BBC4, far from being the low-budget, narrow-remit channels much criticised by publicity-conscious politicians, should together be the British HBO, the home of well-made, brave, original programming that allows talent to play to its strength.

Why is television always on the defensive? It's the dominant art form in Britain and we should glory in its power to touch the imagination. Obviously I approach this from the perspective of drama, but drama defines television as much as anything - it's an emotional and intellectual experience. It has the potential to stay with viewers and affect them deeply.

You read the My Media column in MediaGuardian and people are always pretending they don't watch television. Of course they do. The industry has had a traumatic year - for a number of reasons - but there's been a real burst of big, ambitious, high-end drama this month across all the main terrestrial channels. Compare this to the state of theatre: I can't think of a single new British play currently on in the West End.

Even with the proliferation of digital channels, the demands of the audience really haven't changed that much. In 1980, my BBC2 drama Caught on a Train managed three million viewers. Twenty-seven years later Capturing Mary aired on BBC2 against I'm a Celebrity and got . . . three million viewers.

What do audiences want? In all areas of television they hunger for surprise. Every hit from Life on Mars to Monty Python has dramatic surprises.

Commentators severely underestimate the intelligence of viewers. Many of them enjoy returning to comfortable programmes like Doc Martin, but a large number - and I include the audience from my shows - also want surprises. They want television to enrich their lives and let them see the world afresh, not just fill a space in their evening. If you commission it, the viewers do turn up.

With so many channels, the collective experience is gradually being whittled away, but digital has been great for both niche viewing and for offering repeats. If you spend millions on a production it makes no sense at all to show it once and never again, and it's a complete red herring to think that viewers never want to see a programme twice.

Digital channels also encourage experimentation and risk-taking from new writers. It's a very interesting time for television, and the future is there to be fought for.

Jane TranterController of BBC Fiction

We're quite backward in how we write about television. You'd never dream of clumping all "live performance" together as an art form, and yet you can read the same commentator discussing Nigella Lawson, Dame Judi Dench and Jeremy Paxman in an article, when they're simply not comparable. That's why we get so confused when we try to discuss it. Television itself is not an art form, only the vehicle. It's the individual programmes within it that matter.

Television exists to illuminate and to entertain. It holds a mirror to our lives, either directly (through news and current affairs), or indirectly (through comedy or drama), and allows us to escape our existence by entering worlds different to our own.

Compared to other countries we do bloody well, right across the channels. If you set yourself high enough standards you're occasionally going to fall short and someone's going to take a pop at you, but the day the BBC stops being discussed is the day we should turn the lights off and go home. The big channels that are to survive will need to know exactly who and what they are. But the BBC can't just be big in TV and radio - bbc.co.uk is going to have to grow even faster than it already is.

Broadcasting directly into people's homes - into their bedrooms and sitting rooms - is an incredibly intimate act, and something we totally and utterly take for granted. We're very lucky with the television we have in the UK. Bringing the world to people is the most wonderful and glorious thing.

Peter BazalgetteChief creative officer, Endemol

Once TV's purposes were cultural, democratic and economic. This was a sustainable argument when telly was special - one and then two channels in the 1950s with heavy public service regulations. Later came Channel 4, with the clear economic purpose of creating independent production. But now TV's not special, it's ubiquitous. And the images on our TVs, mobiles and laptops may or may not emanate from a "television" company. If you asked consumers of television what it's for they'd give you some politically correct guff about news and nature documentaries. But if you charted their viewing you'd establish the overwhelming purpose of television is really to entertain. That is why it remains the only genuine mass medium. Further than that we can only examine television's major players one by one to define, or redefine, their purpose:

BBC - needs to be debated from scratch to decide whether it gets a licence fee at all in ten years' time. The new agenda in favour is that it should be a trustworthy voice amid the gossip, rumour and paranoia of the internet.

ITV - has to redefine its model from that of a broadcaster to a creator of branded content whose channels are just one way of distributing its shows. It needs to be freed from Ofcom's apron strings - why is a regulator still deciding how many ads it can run? That's for consumers to judge.

Channel 4 - has to be the home of the individual voice (writers, directors, or even would-be celebs) which swims against the tide. And if it's genuinely radical it'll keep its younger constituency. If not, Gordon Brown has an alternative.

BSkyB - for selling subscriptions to people who want entertainment and communications.

Virgin Media - see BSkyB above and dilute. All the others must find well defined niches or perish.

Julian BellamyDirector of programmes, Channel 4

The methods of delivery may be mutating and multiplying quicker than a genetically modified mouse, but the essential purposes of television change little - at its most fundamental it's still a medium for communicating narratives that entertain and/or inform. The balance between entertainment and information varies depending where in the world, which channel or what programme you're watching, but all audiovisual content should at least aspire to delivering one or both of those ends.

What new digital technologies bring with them, however, is infinitely greater choice for individuals about how and what they watch (as well as what media they consume); the perception is growing that empowering TV audiences to choose has skewed the balance permanently towards entertainment and away from information.

At Channel 4 we are more usually asked "what is Channel 4 for?" We exist also to entertain and inform, but not in the same fashion as our rivals, acting rather as a catalyst for change, ensuring the pool of ideas and talent is refreshed. We aim to bring new voices and talents into the mainstream, challenging our audience to sample them rather than return to what has been proven to amuse and engage. We aim not to recirculate the same information available elsewhere, but to offer different accounts and perspectives and give greater emphasis to fresh and less familiar sources that might encourage our audience to see their world through new eyes.

Alex Graham Chief executive, Wall to Wall Productions

I'm a child of the television age. Born just after the Coronation and some years before Coronation Street, we didn't have many books in our house and it was television which imbued me with - and to a large extent satisfied - my thirst for knowledge. It was television which made me laugh and made me cry and taught me the power of storytelling.

And even in today's saturated universe, television remains for me the most powerful medium in the world. Sure, the internet can deliver me information on everything from train times to football scores. But it still can't transport me in that way that television can, to the far flung reaches of this world or the even further flung reaches of Russell T Davies's imagination.

Not only that but I think the golden age of television is only just beginning. The combination of the plasma widescreen and high-definition images means that television packs a bigger emotional punch than ever before. The arrival of digital storage means that lovers of television can at last begin to access the remarkable canon of work the medium has produced in the past 50 years. And the democratisation of video technology means the next generation understand the language of television as well as - if not better than - they understand the spoken or written word.

Sadly, much of this has been lost in the recent orgies of self-flagellation and I suppose the only depressing thing about this article is that we feel the need to ask this question in the first place. So here's a suggestion. Let's use this opportunity to reassert a bit of cultural optimism. Let's proclaim television's right to sit at the very heart of our cultural life and celebrate its infinite capacity to adapt to the needs and passions of each new generation.

Jay Hunt Director of programmes, Five

At its best, television entertains us, whether that be in a laugh out loud or a "I never knew that" kind of way. But in Britain it has a more profound cultural role too. It's remarkable that with so many other demands on people's time, television remains such a magnetic draw. Just look at an average Saturday this autumn. The five main terrestrials alone have regularly attracted combined audiences that are just shy of 20 million.

That's all about shared experience. Television still has the ability to bring people together, to create communities with something in common on a scale no other medium can really rival.

That remains incredibly potent because it means TV not only reflects popular culture but defines it. You only have to look at the success of list shows to see how integral iconic programmes are to our sense of history.

I have seen this from the outside as an Australian looking in. I learnt quickly that without a working knowledge of Mr Benn and The Clangers you were a social embarrassment waiting to happen. Even at the ripe old age of 40 you rarely get through an evening out without some sort of nostalgia fest about much-loved shows. TV engages, it diverts but it also makes us feel like we belong.

Daisy Goodwin Head girl of Silver River productions

I grew up in a house where TV was banned so when I left university television was, for me, not just a treat but also I genuinely believed, a benign cultural force. Because I didn't spend my teenage years wincing at The Generation Game I thought that everyone found television as engaging and stimulating as I did. I doubt if many of the 20somethings in my company feel the same. For them TV is a means to an end not a vocation. But it is is absolutely wrong to dismiss TV as just "chewing gum for the eyes'. I have been making a series where we look at the relationship between television and the social history of the past 50 years and it is a fascinating question whether television "holds a mirror up to nature" or whether it is itself the engine of social change. Who really heated the property boom? The Bank of England or the breathy tones of Sarah Beeny? Who would we rather have running the Met Police force: Ian Blair or Helen Mirren's character in Prime Suspect? Did It's a Royal Knockout finally do for the Civil List? Is TV watching us or are we watching TV?